Appearing about 2.5 million years ago, Homo habilis, also known
as "handy man," was a turning point in human evolution because brain
enlargement was truly dramatic. This was revealed through skulls found in
Africa, which exhibited a rounded cranium resulting from the increase in
brain capacity. The brain capacity is larger by 21% than
its most likely ancestors. Perhaps because of an advanced mental connection,
Homo habilis developed a characteristic that is uniquely human,
the technique of making tools. Less than 1.52 meters
tall and weighing under 45 kilograms, it is debatable that habilis
hunted. Most likely they were scavengers instead, supplementing
a mostly vegetarian diet with meat left over from predators' kills.

The most complete hand of Homo habilis found in Olduvai Gorge,
the structure of which was compatible with an ability to make tools.
Stone artifacts, choppers of the Pebble industry and sharp flakes of the
Oldowan technology, first appear in the record about 2 million years ago.
According to some estimates this coincides with the evolution of Homo
habilis . Such an estimate neatly falls in with the tendency to
view stone tool making as a uniquely human, namely Homo, ability.

The most significant fossil is the isolated femora found in East Rudolf.
These femora do not differ from those of modern humans in any feature
related to movement or posture. However, they differ, in very subtle
ways, from the femur of australopithecus. The head of the
femur, where it joins the pelvis, shows change, though its functional significance
is unclear. They may not have to do with locomotion as they do with
widening of the pelvis to allow for the birth of bigger brained, larger headed
babies. In addition, whereas
the shaft of australopithecines femur was columnlike, the femur of habilis
, like modern humans, has a "waisted" shaft that narrows towards the
middle. The teeth and
jaws of Homo habilis are quite similar in size and proportions to
those of the less specialized, earlier australopithecus species.
The back teeth are large, and the incisors are not disproportionately smaller.
The molars of habilis are somewhat more narrow than the typical
australopithecus, and in later species they are clearly
smaller. These changes
suggest that tools were now being used to do part of the molars' job of
crushing and grinding foods. The incisors, however, remained large.
This indicates that they had an important function, perhaps related to meat
eating. Since cooking meat had not yet been developed, habilis
needed a substantial set of incisors for tearing tough raw meat and gnawing
it off bones.

Homo habilis survived for half a million years or more, becoming
a taller, stronger, smarter species of human.

Appearing about 1.9 and 1.2 million years ago, Homo ergaster
had a higher skull dome, thinner cranial bones, slim brow ridges, a light
skull, and generally lighter build than Homo erectus. It
had a swift gait, with long well muscled limbs, and narrow hips.
The body shape and proportions were very similar to modern humans living
in tropical climates. One of the
most spectacular and important paleoanthropological finds in recent years
was the "Nariokotome Boy." This find represents the most complete early
hominid ever found, with almost the entire cranium, and most of the postcranial
material intact. This specimen has been attributed as a male Homo
ergaster by some, though most place it in Homo erectus, and
that is where it will be discussed in detail.

There were seven autopomorphies that are characteristic to Homo erectus
, but which Homo ergaster lacks. These traits link Homo
ergaster to Homo sapiens, and that distinguish Homo ergaster
from Homo erectus:

However,
these traits have been found in the Asian Homo erectus, further confusing
the issue of who is closer to Homo sapiens. In short,
Homo ergaster does not show significant promise of lasting
as a separate taxon due to several factors. It has not been shown to
significantly different from Homo erectus to require the designation
of a new hominid species, and it has not been shown to be closer to modern
humans morphologically as has been claimed by some. At this time,
Homo ergaster basically means early Homo erectus from Africa.

Appearing about 1.8 million years ago, Homo erectus left Africa
and spread to Europe, Indonesia and China. Its cranial capacity was
from 800 to 1200cc. It featured a long, low cranium, with prominent
browridges, and thick skull bones. It had large incisors and
canines, but small molars and premolars. The incisor teeth of Homo
erectus generally have a "scooped out" appearance on the tongue side. Its body
size was approximately the size of Homo sapiens. Its postcrania
(arms and legs) had a robust build but were distinctly human. This
may be because we sit behind a desk and Homo erectus actively used
their arms and legs more throughout the day. There was a significant
increase in body size compared to earlier hominids. Past estimates
were in the 5- 5 1/2 foot range for adult males and around 100 pounds or a
bit more. The discovery
of "Turkana Boy" in 1984 brought this into question. It is the most
complete and the earliest of this species discovered so far. The boy
was only 12 years old when he died but already 5 feet 3 inches tall.
If he had lived to adulthood, he very likely would have grown to 6 feet.

Homo erectus used the Acheulian tool kit, which
consisted mainly of choppers, hand-axes, and scrapers. Scientists are
sure that Homo erectus hunted. The evidence
includes traps and cut marks obviously made under that of a carnivore tooth
mark. Homo erectus was the first known to
use fire. This is supported by charred bones and stones found in the
many Homo erectus sites all over the world.
Fire provided a great number of advantages, including warmth, light, safety
from predators, and cooked food (easier to digest). It was fire that
allowed Homo erectus to migrate (one of the many
migrations) north into Europe. The earliest sign was in Spain, in which
the northeastern region was inhabited by Homo erectus more than 800,0000
years ago. It arrived in France at around 450,000 years ago, where
we find temporary huts made of sticks, stuck in the ground and surrounded
by a circle of stones.

The earliest Homo erectus apparently were contemperaries of the late
Homo habilis in East Africa for several thousand
years. This suggests that the immediate ancestor of Homo erectus
was an early Homo habilis or even another yet to be discovered
species of early human.

Late breaking news: In the May 12, 2000 issue of the journal Science
, it was announced that the Homo erectus fossil remains from
Dmanisi in the Republic of Georgia are much older than previously believed.
New dating places them at 1.7 million years ago. It is further suggested
that the Dmanisi skull looks like Homo ergaster, the earliest Homo
erectus -like species from Africa. If this is true, it means
that Homo ergaster did not only live in Africa. The Dmanisi
date also lends credence to the 1.8 million year old date from Java for
Homo erectus.

The first specimen of Homo heidelbergensis was found in 1907
at the Mauer sand pits near Heidelberg, Germany.A nearly complete
mandible was discovered by a quarry worker. The archaeologist Otto
Schoetensack named the hominid mandible H.heidelbergensis. This particular
find dates to roughly 500,000 years ago.Homo heidelbergensis
existed during parts of the Lower Pleistocene into the Middle Pleistocene.
From approximately 800.000 years ago until the appearance of anatomically
modern humans Homo sapiens.Remains were found
in Europe and Africa.Little is known
so far about how this group fit into the hominid timeline, but it is thought
to have possibly evolved into Homo sapiens (perhaps with an intermittent
species not yet found) and Homo neanderthalensis.

H. heidelbergensis is identifiable by its robust cranium and strong dental
features. Heidelbergensis also shows an increased brain size compared
to H.erectus.

Distinguishing features are: -
an increase in brain size (early Homo approximately 900 cc,
heidelbergensis specimens approximately 1200cc). -
a shift from the widest part of the brain case from the cranial
base to the parietal regions. -
the rear of the cranial vault becomes more vertical. -
a gradual reduction in cranial robusticity. -
a decline in post cranial robusticity -
a more prominent face and nose -
a tendency for a shift from shorter more robust stature to taller
more leaner bodies.

Some major findings of H.heidelbergensis are located at Atapuerca.Spain.
1300 human fossils representing 30 individuals have been found. They date
between 780.000 years and 300,000 ago.

H.antecessor was first discovered in Gran Dolina at Atapuerca, Spain
in 1995.The new species
was named H.antecessor by J.L. Arsuaga. The species was named antecessor
meaning explorer in Latin. He was probably the first one to "explore" Europe.
According to Jose Maria Bermudez he is the oldest known European and
appears to be forebearer to H.sapiens and H.neanderthalensis
.He lived during
the lower Pleistocene at approximately 800.000 years ago.

H.antecessor shows a mixture of "archaic" and "modern" traits, with
an especially modern-looking mid face. "This combination
of characteristics is unique. It doesn't appear in any other hominid,"
said Antonio Rosas, a co-author of the study published in Science. "From
a logical viewpoint, it fits into an easily definable space, the common
ancestor of Homo sapiens and Neanderthals
."

The more modern facial characteristics of Homo antecessor have
previously only been seen in hominids more than half a million years younger.
In other respects it more closely resembles Homo ergaster, a very
primitive hominid.

Living in forests of oak, pine and beech trees, these hominid ancestors
were most likely hunter gatherers. Human tooth marks on human bones
indicate cannibalism.

The find breathed new life into the argument for the validity of
H. heidelbergensis , aswell as creating
a whole new species: H. antecessor.Anthropologists
will now have to redraw the family tree to include a branch for Homo
antecessor .

Distinguishing features:

- robust figure- brow ridges
are double arched (as is the case
with Chinese H.erectus and Neanderthals)- triple rooted
molars- his brain size
is 1,000 cc.- big jaw like
H.neanderthalensis- cheekbones and
nose like H.sapiens- small post canines
like H.habilis or H. rudolfensis

Homo neanderthalensis was first discovered in 1856 in the Neander
Valley near Duesseldorf, Germany. Workmen in a limestone cave found the
remains of a skull, hip bones and other parts of the skeleton.Johann Carl Fuhlrott,
a local naturalist and the anatomist Hermann Schaffhausen, were the first
one's to identify the bones as hominid.

H. neanderthalensis existed during the cold climate of the pleistocene
from
ca. 200.000 ago until 30.000 years ago when the species became extinct.
Neanderthal sites were found in Europe and the Middle East.

Neanderthals created Mousterian stone tools including spears, using
a core and flake technique during the Middle Palaeolithic period.

They hunted for meat and cracked open animal bones to get at the marrow
. Researchers found a high concentration of break and cut marks on animal
bones indicative of butchering at Kobeh Cave. They were probably
omnivores but behaved as carnivores, with animal protein being their main
source of dietary protein.

Neanderthals created ornaments for personal adornment. They buried most
of their dead in a flexed position.The graves sometimes contained
gifts. For example stone or bone implements, ochre or animal bones
and flowers.

Even though H.sapiens and H.neanderthalensis were contemporaries
for approximately 10.000 years recent DNA studies seem to indicate that
there was no interbreeding between H.neanderthalensis and modern
H.sapiens.

Their distinguishing features are:

- short and stocky approximately 1,5 m (5 ft) high with large joints- great muscular
strength- prominent brow
ridge- forehead slopes
sharply back- occipital bun
(protrusion at the back of skull)- low cranium
with a long face- nose and teeth
sit farther forward than in other hominids- large brain- vocal capabilities

The oldest known Homo sapiens remains are 100.000 years old and
were found in several places in South Africa.

Approximately 50.000 years ago H.sapiens moved into western Asia
and then into Europe.During this time
of the Upper Palaeolithic( 40.000 B.P. - 10.000 B.P.) an innovation explosion
occurred.H. sapiens
created an extensive tool kit out of stone. Blades, scrapers and projectile
points were manufactured using a special flaking technique. Materials such
as bone,antler,wood and ivory were used for spears as well as bow
and arrows.

The Upper Palaeolithic shows evidence of elaborate human burials, cave
art, portable art, personal adornments, and decorated tools. Also a dramatic
change in human behaviour occurs, which becomes apparent in more efficient
foraging strategies and complex social organizations. It is assumed that
an increase in brain size as well as the development of language is responsible
for those changes.

The pictured skull is called Cro Magnon.It is 30.000 years
old and the oldest European H.sapiens found in France.

There is still disagreement among scientists about the origin
of theseanatomically modern
humans. Two scenarios have been proposed:

a) The "Multiregional Hypothesis" states that all modern humans evolved
in parallel from earlier populations in Africa, Europe and Asia, with some
genetic intermixing among these regions. Support for this comes from the
similarity of certain minor anatomical structures in modern human populations
and preceding populations of Homo erectus in the same regions.

b) The "Out of Africa Hypothesis" proposes that a small, relatively
isolated population of early humans evolved into modern Homo sapiens
, and that this population succeeded in spreading across Africa,
Europe, and Asia -- displacing and eventually replacing all other early
human populations as they spread. Part of the evidence to support this
theory comes from molecular biology, especially studies of the diversity
and mutation rate of nuclear DNA and mitochondrial DNA in living human
cells. From these studies an approximate time of divergence from the
common ancestor of all modern human populations can be calculated. This
research has typically yielded dates around 200,000 years ago, too young
for the "Multiregional Hypothesis." Molecular methods have also tended to
point to an African origin for all modern humans, implying that the
ancestral population of all living people migrated from Africa to other
parts of the world.